v4n3 - Breaking a Bad Habit

Of the 45 million smokers in the United States, 70 percent want to quit. Many people relapse when trying to quit smoking, but support and cessation aids help increase long-term success rates.

Nicotine-replacement therapy (NRT) uses a step-down approach with different nicotine strengths. Nicotine gum, nasal spray or the lozenge Commit® suppress immediate cravings by releasing the addictive chemical for quick absorption into the bloodstream. Nicotine patches release the chemical over a longer period of time. The Straw™, currently in phase III trials, contains small beads of nicotine that are ingested for immediate relief. The disposable plastic straw delivers as much nicotine as other NRTs.

Zyban® (bupropion), known as the antidepressant Wellbutrin®, is the only non-nicotine FDA-approved drug for smoking cessation. Nicotine withdrawal symptoms are similar to depression, making Zyban, and other antidepressants used off-label, effective for smoking cessation. Zyban combined with NRT may improve quit rates. A major study showed that smokers using both Zyban and nicotine patch had a higher one-year continuous quit rate (23 percent) compared with either treatment alone (18 percent and 10 percent, respectively). Common side effects of Zyban include insomnia, nausea and headache.

Another non-nicotine drug called varenicline helped about half of smokers quit compared with Zyban in a phase II clinical trial. Varenicline, now in phase III, targets receptors in the brain to block the pleasure of smoking and reduce nicotine cravings and withdrawal symptoms.

Acomplia™ (rimonabant), also in phase III testing, suppresses cravings for food and narcotics in the brain’s hypothalamus by blocking receptors in the brain. Recent research showed that nearly a third of smokers quit for a longer period of time than smokers trying to quit without taking the drug. Currently under FDA review, Acomplia will likely gain approval for treating obesity in 2006.

A novel option for combating nicotine addiction uses the body’s immune system. Typically, nicotine travels from the lungs into the bloodstream and enters the brain after crossing the blood-brain barrier. Nicotine binds to nerve cell receptors and causes a stimulatory response. A vaccine called NicVAX™ stimulates production of antibodies that bind to nicotine molecules, preventing them from crossing the blood-brain barrier. The “high” normally caused by nicotine does not occur, making it easier for people to quit. In a phase II test, NicVAX lowered nicotine levels in the brain 64 percent.

Studies show that combining cessation treatment with social or behavioral support carries the best chance for long-term success. Visit www.smokefree.gov for more on how to quit smoking.